A known lens drive unit for an imaging device mounted in a cellular phone incorporates a smooth impact drive mechanism (SIDM: a registered trademark).
Japanese Unexamined Patent Publication No. 2015-089183, for example, discloses a lens drive unit that incorporates the smooth impact drive mechanism. This lens drive unit comprises an actuator including a piezoelectric element having a rectangular columnar shape, a weight joined with one end face of the piezoelectric element in a direction of extension and contraction of the piezoelectric element, and a drive shaft joined with the other end face of the piezoelectric element in the direction of extension and contraction of the piezoelectric element. The weight of the actuator is fixed to a base member and a friction engagement unit frictionally engages an outer periphery of the drive shaft of the actuator. In the lens drive unit described above, extension and contraction of the actuator is imparted to the drive shaft and the friction engagement unit frictionally engaging the drive shaft with a predetermined friction force is driven by making use of a difference in speed between when the actuator extends and when the actuator contracts.
The friction engagement unit includes a lens frame fitted with a lens having an optical axis extending in parallel with a direction of extension and contraction of the actuator. Causing the friction engagement unit to advance and retract in the direction of extension and contraction of the actuator results in the lens frame advancing and retracting.
In the lens drive unit described above, the lens frame of the friction engagement unit is displaced with respect to the base member in a direction orthogonal to the direction in which the friction engagement unit advances and retracts to press the drive shaft by impact from an outside of the lens drive unit or the like. In this case, the piezoelectric actuator is inclined with respect to the base member, the weight of the actuator is dislocated from the base member, and an electric wire for applying voltage to the piezoelectric element of the actuator is broken, resulting in a short-circuited electric wire.
The present disclosure provides a lens drive unit that offers enhanced reliability in connection between an actuator electrode and an electric wire.